<script lang="ts" setup name="XtxCarousel">
// 坑：script中如果不写东西，name不起作用！！！
import type { BannerItem } from '../../types/data'
// import type { PropType } from 'vue';
import { onMounted, onUnmounted, ref } from 'vue';

// BannerItem[]
// 1, js的defineProps (对象的写法)
// const props = defineProps({
//     slides: {
//         type: Array as PropType<BannerItem[]>,
//         required: true
//     }
//     autoplay:{
//         type:Boolean,
//         default:false
//     }
// })
// 2，defineProps<props类型>()
const { slides, autoplay = false, duration = 3000 } = defineProps<{
    slides: BannerItem[],
    autoplay?: boolean,
    duration?: number
}>()
const active = ref(0)

const onPrev = () => {
    active.value--
    // 如果active.value小于小标的最小值，归到下标的最大值去
    if (active.value < 0) {
        active.value = slides.length - 1
    }
}
const onNext = () => {
    active.value++
    // 如果active.value 溢出了下标的最大值，归0
    if (active.value >= slides.length) {
        active.value = 0
    }
}


const play = () => {
    // 如果不希望出现进入页面自动轮播
    if (!autoplay) return
    // 在模块化环境编写代码时，定时器延时器，编辑器会识别成node中的定时器延时器
    // 我们要的是浏览器端的
    clearInterval(timer)
    timer = window.setInterval(() => {
        console.log('轮播图，正在轮播中')
        onNext()
    }, duration)
}

const stop = () => {
    clearInterval(timer)
}

// 定时器逻辑，控制轮播 （模拟用户访问的过程）
let timer: number = -1
onMounted(() => {
    play()
})

// onDestroyed
onUnmounted(() => {
    clearInterval(timer)
})

</script>

<template>
    <div class="xtx-carousel" @mouseenter="stop" @mouseleave="play">
        <!-- 轮播图主体 轮播图片 -->
        <ul class="carousel-body">
            <li v-for="(item, index) in slides" :key="item.id" class="carousel-item"
                :class="{ fade: active === index }">
                <RouterLink to="/">
                    <img :src="item.imgUrl" alt="" />
                </RouterLink>
            </li>
        </ul>
        <!-- 左边箭头 -->
        <a href="javascript:;" class="carousel-btn prev" @click="onPrev"><i class="iconfont icon-angle-left"></i></a>
        <!-- 右边箭头 -->
        <a href="javascript:;" class="carousel-btn next" @click="onNext"><i class="iconfont icon-angle-right"></i></a>
        <!-- 小圆点 -->
        <div class="carousel-indicator">
            <span v-for="(item, index) in slides" :key="item.id" :class="{ active: active === index }"
                @mouseenter="active = index"></span>
        </div>
    </div>
</template>

<style scoped lang="less">
.xtx-carousel {
    width: 100%;
    height: 100%;
    min-width: 300px;
    min-height: 150px;
    position: relative;

    .carousel {
        &-body {
            width: 100%;
            height: 100%;
        }

        &-item {
            width: 100%;
            height: 100%;
            position: absolute;
            left: 0;
            top: 0;
            opacity: 0;
            transition: opacity 0.5s linear;

            &.fade {
                opacity: 1;
                z-index: 1;
            }

            img {
                width: 100%;
                height: 100%;
            }
        }

        &-indicator {
            position: absolute;
            left: 0;
            bottom: 20px;
            z-index: 2;
            width: 100%;
            text-align: center;

            span {
                display: inline-block;
                width: 12px;
                height: 12px;
                background: rgba(0, 0, 0, 0.2);
                border-radius: 50%;
                cursor: pointer;

                ~span {
                    margin-left: 12px;
                }

                &.active {
                    background: #fff;
                }
            }
        }

        &-btn {
            width: 44px;
            height: 44px;
            background: rgba(0, 0, 0, 0.2);
            color: #fff;
            border-radius: 50%;
            position: absolute;
            top: 228px;
            z-index: 2;
            text-align: center;
            line-height: 44px;
            opacity: 0;
            transition: all 0.5s;

            &.prev {
                left: 20px;
            }

            &.next {
                right: 20px;
            }
        }
    }

    &:hover {
        .carousel-btn {
            opacity: 1;
        }
    }
}
</style>